Design And Research Of Phase-Shifted Full-bridge DC/DC Converter

With China’s rapid economic development, electronic technology and computertechnology become more and more widely. It makes the power supply develop in the directionof lighter, smaller, high-frequency and high-efficiency. While increasing the operatingfrequency, the power switch voltage and current stress increases as well.Soft-switchingtechnology can achieve zero-voltage start or zero current shutdown. It can also improve theefficiency and reduce the electromagnetic interference. In the field of high-powerapplications,the phase-shifted full-bridge DC/DC converter has a simple circuit structure, asmall switching loss, and it is easy to control.So it has been generally applied on manyoccasions.This paper focuses on the characteristics of the phase-shifted full-bridge ZVS DC/DCconverter and analyses its operating principle. By adding a secondary network, this papersolves the problems in phase-shifted full-bridge ZVS DC/DC converter such as the duty cycleloss, different zero voltage conditions in two bridge arms, and the loss of power supply. Thispaper also models and simulates the phase-shifted full-bridge DC/DC converter.In order to resolve the defects in phase-shifted full-bridge DC/DC converter, a saturableinductor of the converter is put forward. Then its working principle is analyzed. Designedcircuit structure of the conventer and main circuit parameters of the system, includinghigh-frequency transformer, switch, input filter capacitor, output filter inductor and capacitor,resonant inductor and blocking capacitors. The establishment of small-signal model of theconverter is based on the Buck circuit. Using MATLAB software simulates the PID control,fuzzy control and fuzzy PID control. The results shows that fuzzy PID control has optimalcontrol effect.